Deposits on Top of Water Heater

[C317414]

Hello,

I have a GE-branded, natural gas water heater that I installed in 9-10 years ago. I've noticed some deposits on top of the heater (see photos) in the last two years or so. The deposits appear to be from a leak, or condensation, but they are totally dry. There's no evidence of a water leak in the ceiling above the heater.

I'm not sure if this makes a difference, but the heater and the gas furnace used to share the same flue pipe. The furnace was replaced with a ultra high efficiency one two or three years ago, and now the only appliance using the original flue pipe is the water heater.

Has anyone seen something like this before? Does anyone know what the cause may be?

Thanks!

 

[Fitter30]

Wouldn't be surprised if there was a small leak on the hot side from all the mineral deposits and the deposits have the leak stop. If it was condensation it would be on the cold side.

 

[Sponsor]

 

[John Gayewski]

You have a leak.

 

[Dj2]

Yes, a leak can cause this.
Look at the nipples first.

 

[Reach4]

Couldn't it be rain plus combustion products?

 

[C317414]

Thanks for all the replies. I'll check more carefully for evidence of a leak. I'll also take a close look during a heavy rain to see if it's related to water coming down the flue.

 

[WorthFlorida]

The exhaust from the water heater is CO2 and water vapor. It hits the cold flute and condenses. A very weak solution of carbonic acid forms with the presence of oxygen. Perhaps there isn't enough draft up the chimney. Without a furnace keeping the chimney good and hot for a good draft, a water heater may not be getting the chimney hot enough. Of course do look for a leak but why isn't wet. Yes, possible rain water is causing it.

 

[Terry]

I removed this water heater on Thursday.
The tempering valve was hand tight, the 3/4" nipple from the tee on the right looked to be closed off, it was time for a new water heater. There was a lot of sediment in the tank too.

 

[Reach4]

I vacuum the top of my gas water heater maybe every 5 years.

 

[C317414]

Followup:

The water heater had a small leak at the outlet nipple. It was not immediately visible because of the pipe insulation. I ended up replacing the heater anyway, because of it's age and the fact that it was producing water with bad odor. The new heater has an impressed current anode to prevent the smell.

Thanks for all the feedback.